Roll

ABSTRACT

The invention relates to a roll of material sheets, which material sheets have a longitudinal direction and a transverse direction, wherein the roll includes discrete material sheets. The material sheets are folded at least once in the longitudinal direction, which direction corresponds to the winding direction of the roll. The material sheets being interlinked in such a way that, when a first material sheet is extracted, a predetermined part of a subsequent material sheet is fed out.

TECHNICAL FIELD

This invention relates to a roll of material sheets folded at least oncein the longitudinal direction, which direction corresponds to thewinding direction of the roll. The material sheets being interlinked insuch a way that, when a first material sheet is extracted, apredetermined part of a subsequent material sheet is fed out.

BACKGROUND ART

A common solution for dispensing material for drying or wiping is toprovide a roll of wound paper or tissue in a suitable dispenser. Rollsof this type are usually of the centrefeed type, wherein a web of paperis removed from the centre of the roll. However, the problems listedbelow will also apply to rolls where a web is dispensed from the outerperiphery of the roll, sometimes referred to as “perifeed” rolls. Whenplaced in a dispenser, a user will withdraw a desired length of paperand tear it off using a serrated edge provided on the dispenser. Aproblem with this solution is that it may be difficult to estimate thelength of the withdrawn web and that the serrated edge tends to resultin an uneven edge. In addition the wound web will be dispensed in atwisted, spiral form that must be straightened before used. To overcomeat least some of these problems, the paper web may be perforated atregular intervals. This may at least partly alleviate the problem of anunsightly, uneven edge provided that a perforated line is present nearthe portion that the user wishes to tear. However, the problem of thetwisted, spiral web is not resolved by perforating the paper web.

It is an object of the present invention to solve the above problems byproviding an improved centrefeed or perifeed roll for use in a dispenserarrangement for dispensing material from a wound roll.

DISCLOSURE OF INVENTION

The above objects are achieved by means of a roll of material sheetsaccording to claim 1 and its dependent claims.

In the subsequent text the terms “longitudinal” and “transverse” areused to define the relative position of a material sheet relative to thedirection of feed of the sheet. The direction of feed coincides with thelongitudinal axis of the material sheets. These terms are notnecessarily related to the relative size of the side edges of a materialsheet. Similarly, the terms “preceding” “and “subsequent” or “front” and“rear” are used to define the relative position of a material sheet inrelation to adjacent sheets in relation to the direction of feed of thesheets.

A roll made from an assembled web of discrete sheets arranged accordingto any of the embodiments described below may be a centrefeed roll,whereby the material sheets are extracted from the centre of the roll,or a peripheral feed roll, sometimes termed “perifeed” roll, whereby thematerial sheets are extracted from the outer periphery of the roll.

According to a preferred embodiment, the invention relates to a roll ofmaterial sheets, which material sheets have a longitudinal direction anda transverse direction. The roll comprises discrete material sheets,which material sheets are folded at least once in the longitudinaldirection, which direction corresponds to the winding direction of theroll. The assembled web may comprise a single line of material sheetscut from a continuous length of material. Alternatively two single linesof material sheets may be interposed on each other to form a single web.A longitudinal fold line is preferably, but not necessarily arranged sothat the material sheets are folded in half. The material sheets arepreferably interlinked in such a way that, when a first material sheetis extracted, a predetermined part of a subsequent material sheet is fedout.

According to a further embodiment, the material sheets may be foldedtwice in the longitudinal direction of the said material sheets.Preferably, the distance between the parallel fold lines is at leasthalf the width of a sheet in the transverse direction. This type offolding arrangement is sometimes referred to as a C-fold and ispreferably, but not necessarily, performed when the material sheets areplaced in an overlapping relationship.

According to a first alternative embodiment, the interlinking may beachieved by at least partially overlapping adjacent end portions of thematerial sheets. The material sheets may be interlinked by a fixedoverlap of at least 25% of the length of an unfolded material sheet inits longitudinal direction. The overlap may be up to 50% of the lengthof an unfolded material sheet in the longitudinal direction. Thisoverlap may be constant, but can also be variable depending onpredetermined parameters as described below.

For a perifeed roll, the friction between adjacent material sheets maybe substantially constant from the outer periphery to the centre of theroll, as subsequent material sheets are continuously exposed by theremoval of preceding material sheets. In this case, the overlap may besubstantially constant. The overlap may be selected in the range 25-50%of the length of an unfolded material sheet in its longitudinaldirection, depending on the properties of the material sheets. Examplesof such properties may be the surface structure or the physical size ofthe material sheets.

According to a second alternative embodiment, the degree of overlap maybe arranged to be proportional to the radius of the roll, so that theoverlap varies from the centre of the roll to the outer periphery of theroll. For instance, for a centrefeed roll, the friction between adjacentmaterial sheets may be larger near the centre of a roll, due to arelatively higher roll density of the material sheets and a relativelyrestricted central opening available for withdrawing sheets through theroll. As sheets are withdrawn, the roll density may be reduced and theopening at the centre of the roll increases, so that the friction forcesbetween adjacent material sheets are reduced. In this case, the degreeof overlap may be at least 25% of the length of an unfolded materialsheet in its longitudinal direction at the centre of the roll, whereinthe overlap increases in the direction of the outer periphery of theroll. The degree of overlap may be increased up to 50% of the length ofan unfolded material sheet in the longitudinal direction at the outerperiphery of a full roll.

For a centrefeed roll, the friction between adjacent material sheets maybe larger near the outer periphery of a roll, due to the roll weightrequiring a relatively higher force for withdrawing each sheet when theroll is first started. As sheets are withdrawn, the roll weight isreduced and less force is required for withdrawing sheets. Hence thefriction forces between adjacent material sheets may be reduced towardsthe centre of the roll. In this case, the degree of overlap may be up to50% of the length of an unfolded material sheet in its longitudinaldirection at the outer periphery of a full roll, wherein the overlapdecreases in the direction of the centre of the roll. The degree ofoverlap may be decreased to 25% of the length of an unfolded materialsheet in the longitudinal direction at the centre of the roll.

Alternatively, by controlling the roll density of a roll, in particularof a perifeed roll, during winding, the friction between adjacentmaterial sheets may be kept substantially constant from the outerperiphery to the centre of the roll. In such cases, a substantiallyconstant overlap may be selected in the range 25-50% of the length of anunfolded material sheet in its longitudinal direction, depending on theproperties of the material sheets.

According to a third alternative embodiment of the invention the overlapbetween adjacent material sheets forming a roll may be formed by placingtwo parallel lines of individual material sheets on top of each other.As opposed to the first alternative embodiment, each alternate sheet ofan assembled web is placed with its transverse rear portion arranged ontop of a transverse front portion of a subsequent sheet, and with itstransverse front portion on top of the transverse rear portion of apreceding sheet throughout the said web. This may be achieved by cuttinga continuous web into a first line of sheets and then placing a cut,second line of sheets on top of said first line of sheets. Each line ofsheets of the respective first and second line may be arrangedend-to-end or at a predetermined fixed or variable distance betweenopposing ends of consecutive material sheets.

The interlinking may be achieved by at least partially overlappingadjacent ends of the material sheets. The material sheets may beinterlinked by an overlap of at least 25% of the length of an unfoldedmaterial sheet in its longitudinal direction. An overlap between 25% and50% will require a separation of the individual sheets in each line ofsheets prior to, or subsequent to, the assembly of the first and secondlines of sheets. The overlap may be up to and including 50% of thelength of an unfolded material sheet in the longitudinal direction. A50% overlap merely requires indexing of the cut second line of sheets inthe longitudinal direction prior to placing it on top of the cut firstline of sheets. The overlap may be constant, but can also be variabledepending on predetermined parameters.

The first and second lines of sheets may be placed on top of each otherwith their respective side edges coinciding in a vertical plane, thatis, with a 100% transverse overlap. The transverse overlap may beselected between 30% and 100% of the transverse width of the materialsheets.

According to a first example of the third alternative embodiment, thedegree of longitudinal overlap is 50% of the length of an unfoldedmaterial sheet in its longitudinal direction. The transverse overlap mayin this example be 100% of the transverse width of the material sheets.

The partially overlapping first and second lines of material sheets maybe folded at least once in the longitudinal direction to form anassembled web, wherein the longitudinal direction corresponds to thewinding direction of the material sheets forming the roll. Such alongitudinal fold line is preferably, but not necessarily arranged sothat the material sheets are folded in half. The assembled web may thenbe wound to form said roll of material sheets.

According to a second example of the third alternative embodiment, thedegree of overlap is 50% of the length of an unfolded material sheet inits longitudinal direction. The transverse overlap may in this examplebe 50% of the transverse width of the material sheets.

Preferably, the partially overlapping material sheets may be foldedtwice in the longitudinal direction of the said material sheets. Thedistance between the parallel fold lines may be at least half the widthof each sheet in the transverse direction. The assembled web can beachieved by folding the outer, non-overlapping edge of the lower line ofmaterial sheets inwards over and fully covering the overlap.Subsequently, the outer, non-overlapping edge of the upper line ofmaterial sheets inwards over and fully covering the first folded edgeand the overlap. Alternatively the assembled web is created bysimultaneously folding the outer edge of the lower line of materialsheets upwards and inwards, and the outer edge of the upper line ofmaterial sheets downwards and inwards This type of folding arrangementcreates an assembled web comprising consecutive partially overlappingpairs of substantially V-shaped, opposed and interleaved materialsheets.

The same effect, using partial overlap in the transverse direction maybe achieved at other degrees of overlap. For instance, with a transverseoverlap of ⅓ of the transverse width, the sheets on either side of theoverlap may be folded in half towards to create an assembled web.Alternatively, with a transverse overlap of ⅔ of the transverse width,the sheets on either side of the overlap may be folded along alongitudinal fold line located at approximately ⅓ of the width from theouter edges of the respective of the first and second line of sheets tocover a part of the overlap and create an assembled web.

The examples described above for the third alternative embodiment mayalso apply to examples using a variable overlap in the longitudinaldirection.

The assembled web of longitudinally and transversely overlappingmaterial sheet may then be wound in the same way as described above fora single line of material sheets in order to form a roll.

In addition to the overlap, adjacent material sheets may be interlinkedby one or more alternative arrangements in order to achieve a desiredfriction between at least predetermined parts of the contacting surfacesof said material sheets. By modifying the friction between adjacentsurfaces it is possible to ensure that a first material sheet withdrawnfrom a dispenser will feed out a predetermined portion of a subsequentmaterial sheet. The amount of friction modification is dependent on thequality and surface structure of the material sheets used. For sheetshaving a relatively rough surface structure the friction resulting fromthe overlapped and folded relationship between adjacent sheets may besufficient. In this case, varying the amount of overlap may besufficient to achieve the desired result. On the other hand, formaterial sheets having a relatively smooth surface structure a frictionenhancing process and/or arrangement may be required to ensure that aportion of a subsequent material sheet is fed out by a precedingmaterial sheet.

One alternative way of modifying the friction between overlappingsections of material sheets may be an embossing on at least a portion ofthe overlap. Such an embossing may be carried out by passing anassembled web of pre-cut and partially overlapping material sheetsthrough a nip between a pair of cylindrical rolls. The rolls may bearranged to apply a desired amount of pressure onto at least a portionof the overlapping sections and/or to apply pressure over apredetermined surface area of each overlapping section. One or bothrolls may be patterned in order to emboss the compressed portions to apredetermined degree.

According to a further alternative way of modifying the friction, thematerial sheets may be interlinked by a friction enhancing coatingapplied onto at least a portion of the overlapping sections betweenadjacent sheets. A coating of this type may be applied to at least aportion of one or both ends of each sheet in an assembled web ofmaterial sheets. The coating may be applied by a single roller or a pairof rollers, or by spraying. Coatings of this type may modify the surfacefriction of at least one of the surfaces in an overlapping section. Thecoating may also create a brittle bonding between contacting surfaces.

According to a similar alternative way of modifying the friction, thematerial sheets may be interlinked by a rubber emulsion or an adhesiveon at least a portion of the overlap between adjacent sheets. Suitableadhesives may include liquid, curable adhesives, wax based hot-meltadhesives, friction hot-melt adhesives, adhesives with low adhesion andhigh cohesion, or a weak adhesive applied as multiple spots, such asstarch or polyvinyl alcohol. Such adhesives may be applied in the sameway as the coatings described above. Such a coating or adhesive may beapplied prior to, preferably immediately prior to, the sheets beingdisplaced into their overlapping positions.

According to a further alternative embodiment, the overlap may becombined with an alternative way of interlinking the material sheets.Prior to being placed in an overlapping relationship, adjacent ends ofsheets to be overlapped are folded once along a fold line in thetransverse direction of the respective sheet. Opposing ends of eachsheet are folded in opposite directions so that each material sheet willbe substantially Z-shaped. The distance between a transverse edge of thesheet and an adjacent transverse fold line may be between 5-25% of thetotal length of an unfolded material sheet. The adjacent material sheetsare then interlinked in such a way that each folded end portion enclosesthe adjacent folded end portion. In this way, the end portions ofadjacent material sheets will be overlapping and the folded end portionsof each pair of said sheets may hook into the other. The transversefolding is preferably performed before a subsequent longitudinal foldingof the assembled overlapping material sheets.

Individual sheets in the line or lines of material sheets cut from acontinuous web may be separated by a straight, transverse cut at rightangles to the longitudinal axis of the respective line of sheets.According to an alternative example, the transverse cut may have theshape of a curve having at least one apex, where the apex forms aleading or trailing edge of each material sheet in the line. The apexmay preferably, but not necessarily, coincide with a fold line and thecurve may preferably, but not necessarily, be symmetrical about an axiscoinciding with the said fold line in the plane of the material sheet.

For example, for single line of material sheets placed in a constant orvariable overlapping relationship the cut may have an approximatesinusoidal shape, with a single apex coinciding with a central foldline. Alternatively, if the assembled web has two fold lines, such as aC- or Z-fold, the cut may comprise a substantially sinusoidal curve withan apex coinciding with each fold line. The shape of the cut and thelocation one the at least one apex may also be applied to assembled webscomprising two lines of material sheets. The shape of the curve is notlimited to sinusoidal curves, but may be given any suitable shape havingan apex at leading edge of each material sheet.

Advantages of the transverse cut are that it makes the assembled webeasier to handle during the production stage and that it provides animproved, easy to grasp portion when a subsequent material sheet ispulled out and presented to a user.

Non-limiting examples of suitable materials for sheets for this purposeare suitable tissue products, such as wet crêpe dry crêpe orthrough-air-dried (TAD) materials, which products contain mostly paperpulp. The material sheets may also be made from a suitable type ofnon-woven or equivalent wiping material. The non-woven materials may bespunbond, thermobond, chemically bonded, spunlaced, spunlaid, carded,air laid or entangled non-wovens. The non-woven materials may comprisesuitable natural or manmade fibres, containing cotton or rayon,polypropylene (PP), polyethylene (PE), polyether sulfone (PES),polyethylene terephthalate (PET), polyester, polyamide, bi-componentfibres (Bico) or pulp fibres.

A dispenser for use with a roll according to the invention may beprovided with a dispensing opening through which the material sheets aredispensed. Because a roll according to the invention comprisesindividual material sheets there is no need to provide the dispenserwith tear means adjacent the dispensing opening. However, the dispensingopening can be provided with a serrated edge or similar, in order toallow the dispenser to be used for rolls comprising either separatesheets or a continuous web.

BRIEF DESCRIPTION OF DRAWINGS

In the following text, the invention will be described in detail withreference to the attached drawings. These schematic drawings are usedfor illustration only and do not in any way limit the scope of theinvention. In the drawings:

FIG. 1 shows a lower perspective view of a dispenser provided with aroll of discrete material sheets according the invention;

FIG. 2 shows a plan view of a first part of a process for making a rollof material sheets according to a first embodiment of the invention;

FIG. 3A shows a plan view of a folding process occurring subsequent tothe process of FIG. 2;

FIG. 3B shows a plan view of an alternative folding process occurringsubsequent to the process of FIG. 2;

FIG. 4A shows a side view of a continuous web of material sheetsassembled as shown in FIGS. 2 and 3A;

FIG. 4B shows a side view of a continuous web of material sheetsassembled as shown in FIGS. 2 and 3B;

FIG. 5 shows an alternative longitudinal folding procedure occurringsubsequent to the process of FIG. 2.

FIG. 6 shows a schematic perspective view of the first part of a processfor making a roll of material sheets according to a second embodiment ofthe invention.

FIGS. 7A-B show a plan view of a first part of a process for making aroll of material sheets according to first example of a second preferredembodiment of the invention;

FIGS. 8A-B show a plan view of a first part of a process for making aroll of material sheets according to second example of a secondpreferred embodiment of the invention; and

FIGS. 9A-B show a plan view of a part of a process for making a roll ofmaterial sheets separated by a curved transverse cut.

EMBODIMENTS OF THE INVENTION

FIG. 1 shows a lower perspective view of a dispenser 11 provided with aroll 12 of discrete material sheets 13. The roll 12 comprises discretematerial sheets assembled, folded and wound into a roll in accordancewith the invention. The discrete material sheets are interlinked in sucha way that, when a first material sheet 13 is extracted by a user, apredetermined part of a subsequent material sheet 14 is pulled out ofthe dispenser 11 by the first material sheet 13. The dispenser 1 isprovided with a dispensing opening 15 through which the material sheetsare dispensed. The dispensing opening can be provided with a serratededge (not shown) or similar, in order to allow the dispenser to be usedfor rolls comprising a continuous web.

FIG. 2 shows a plan view of a first part of a process for making a rollof material sheets according to a first embodiment of the invention. Thematerial sheets used in the process have been pre-cut from a continuousweb of material (not shown) in a first step. The resulting materialsheets have a longitudinal direction and a transverse direction. Theprocess involves feeding an assembled web of discrete material sheets21, placed end-to-end in their longitudinal direction, through anapparatus 22 arranged for displacing the discrete material sheets 21 sothat overlap 23 is created by adjacent material sheets in theirlongitudinal direction. This is achieved by controlling the relativespeed of a first and a second conveyor 24, 25. The apparatus 22 fordisplacing the discrete material sheets 21 is provided with a device(not shown) for controlling the vertical position of the front edge of amaterial sheet relative to the rear edge of a preceding sheet isprovided at the location where the material sheets are passed from thefirst to the second conveyor. In the example shown, the length X₁ of theoverlap 23 is ⅓ of the length X₂ of an unfolded material sheet 21. Theoverlap 23 can be increased by slowing down the second conveyor 25 to apredetermined speed relative to the first conveyor 24, and vice versa.As can be seen from the example in FIG. 2, the front portion of eachmaterial sheet is positioned on top of a preceding sheet. Subsequently,the assembled web of overlapping material sheets 21 is fed through anapparatus 31 arranged to fold the sheets 21 along a fold line coincidingwith the longitudinal centreline C_(L) of the material sheets 21, asshown in FIG. 3A. According to the example shown in FIG. 3A, the lefthand side 32 of each material sheet is displaced upwards and folded overthe right hand side 33 of the material sheet 21, as indicated by thearrow B, as seen in the direction of feed, as indicated by the arrow C,of the assembled web of material sheets 21. The overlapping and foldedmaterial sheets 21 can then be fed as a continuous assembled web 34between opposing rollers and/or conveyors (not shown) and issubsequently subjected to a winding operation.

FIG. 4A shows a side view of a continuous web 34 assembled from anassembled web of overlapping and folded material sheets 21 as describedin FIGS. 2 and 3A above. A conveyor supporting the assembled web ofmaterial sheets has been removed for clarity. The assembled web ofmaterial sheets 21 are then attached to a mandrel 41 and subjected to awinding operation, as shown in FIG. 4A. The assembled, discrete materialsheets 21 are wound in the clockwise direction, as indicated by thearrow D, to form a roll 42.

According to an alternative first embodiment, the front portion of eachmaterial sheet is positioned on top of a preceding sheet in the same wayas described in connection with FIG. 2 above. The subsequentlongitudinal folding procedure is similar to the procedure described inFIG. 3A above. As shown in FIG. 3B, the assembled web of overlappingmaterial sheets 21 is fed through an apparatus 31 arranged to fold thesheets 21 along a fold line coinciding with the longitudinal centrelineC_(L) of the material sheets 21. The left hand side 32 of each materialsheet is displaced downwards and folded under the right hand side 33 ofthe material sheet 21, as indicated by the arrow B, as seen in thedirection of feed, as indicated by the arrow C, of the assembled web ofmaterial sheets 21. Hence, the difference between the folding processesshown in FIGS. 3A and 3B respectively is the direction of the arrow B.The overlapping and folded material sheets 21 can then be fed as acontinuous assembled web 34 towards a subsequent winding operation. FIG.4B shows a side view of the continuous web 34 of material sheetsaccording to the alternative embodiment of the invention, prior to thewinding operation. As in FIG. 4A, the conveyor supporting the assembledweb of material sheets has been removed for clarity. The assembled webof material sheets 21 are then attached to a mandrel 41 and subjected toa winding operation, as shown in FIG. 4B. The assembled, discretematerial sheets 21 are wound in the clockwise direction, as indicated bythe arrow D, to form a roll 42.

FIG. 5 shows an alternative longitudinal folding procedure, taking theplace of the procedure described in FIGS. 3A and 3B. According to thisalternative procedure, the material sheets are folded twice in thelongitudinal direction of the said material sheets. The assembled web ofoverlapping material sheets 21 is fed through an apparatus 51 arrangedto fold the sheets 21 along a first and a second fold line F₁, F₂, thatare parallel to the longitudinal centreline C_(L) of the material sheets21. In FIG. 5, the left hand side 52 of each material sheet is displacedupwards and folded along the first fold line F₁, as indicated by thearrow B₁, as seen in the direction of feed, as indicated by the arrow C,of the assembled web of material sheets 21. At the same time the righthand side 53 of each material sheet is displaced upwards and foldedalong the second fold line F₂, as indicated by the arrow B₂. Preferably,the distance X₃ between the parallel first and second fold lines F₁, F₂is at least half the length X₄ of a material sheet in the transversedirection of the material sheets 21. In the schematic example shown, thefirst and second fold lines F₁, F₂ are placed symmetrically on bothsides of the centreline with the distance X₃ being approximately 55% ofthe length X₄ of a material sheet. Alternatively, the same assembled webas shown in FIG. 4 can be used, wherein the folding is carried out inthe opposite direction of the arrows B₁ and B₂, that is, downwards andinwards in the plan view shown. The assembled and folded material sheets21 can then be fed as a continuous web 54 towards a subsequent windingoperation. The winding operation has been described in connection withFIG. 4B above.

The first and second fold lines F₁, F₂ can also be placed asymmetricallyrelative to the longitudinal centreline C_(L) However, the distance X₃between the parallel first and second fold lines F₁, F₂ shouldpreferably not exceed half the length X₄ of a sheet. This type offolding arrangement is sometimes referred to as a C-fold and ispreferably, but not necessarily, performed when the material sheets areplaced in an overlapping relationship.

FIG. 6 shows a schematic perspective view of the first part of a processfor making a roll of material sheets according to a second embodiment ofthe invention. As in the embodiment shown in FIG. 2, the material sheetsused in the process have been pre-cut from a continuous web of materialin a first step. The resulting material sheets have a longitudinaldirection and a transverse direction. The process involves feeding anassembled web of discrete material sheets 21, placed end-to-end in theirlongitudinal direction, through an apparatus 61 arranged for folding thediscrete material sheets 21 so that an overlap 23 is created by adjacentmaterial sheets in their longitudinal direction.

According to this embodiment, the overlap is combined with aninterlinking of the material sheets 21. Prior to being placed in anoverlapping relationship, adjacent front and rear portions 21 a, 21 b ofeach respective sheet is folded once along a fold line arranged in thetransverse direction of the respective material sheet. As shown in FIG.6, the front portion 21 a of each sheet is folded upwards and rearwardsas seen in the direction of feed, as indicated by the arrow C, of theassembled web of material sheets 21. Similarly, the rear portion 21 b ofeach sheet is folded downwards and forwards as seen in the direction offeed. The distance between a transverse edge of the sheet and anadjacent transverse fold line may be between 5-25% of the total lengthof an unfolded material sheet. In the example shown in FIG. 6 thedistance between the transverse edge of each respective sheet and itsadjacent transverse fold line is approximately 15% of the total lengthof a material sheet 21. As seen from the figure each material sheet 21will be substantially Z-shaped and interlinked in such a way that eachfolded front portion 21 a encloses the adjacent folded rear portion 21b. In this way, the front and rear portions 21 a, 21 b of adjacentmaterial sheets 21 will be overlapping in that the folded front and rearportions of said sheets hook into each other. The Z-shape of thematerial sheets in FIG. 6 has been exaggerated for clarity. In fact, theassembled web of assembled and interlocking sheets would besubstantially flat.

The above mentioned transverse folding is performed prior to alongitudinal folding step. The longitudinal folding step involvesfolding the sheets along a fold line coinciding with the longitudinalcentreline of the material sheets, as described in connection with FIGS.3A and 3B above.

FIG. 7A shows a plan view of a first part of a process for making a rollof material sheets according to a first example of a second preferredembodiment of the invention. The process involves feeding two lines ofindividual material sheets in parallel, in the direction of the arrowsA₁ and A₂, and placing on top of each other. This is achieved by cuttingcontinuous webs of material (not shown) into a first line L₁ of sheets71 and then placing a cut, second line L₂ of sheets 72 on top of saidfirst line of sheets. In this example, the sheets 71, 72 of therespective first and second lines L₁, L₂ have the same length X₁ and arearranged end-to-end, with the material sheets 72 of the second line L₂of sheets indexed to form an overlap 73 between subsequent sheets (FIG.7B). The overlap 73 has a length X₂ corresponding to 50% of the lengthX₁ of a material sheet. Each alternate sheet of overlapping web isplaced with its transverse rear portion arranged on top of a transversefront portion of a subsequent sheet, and with its transverse frontportion on top of the transverse rear portion of a preceding sheetthroughout the said web.

As can be seen in FIG. 7B, the first and second lines L₁, L₂ of sheets71, 72 have been placed on top of each other with their respective sideedges coinciding in a vertical plane, that is, with a 100% transverseoverlap Y. The second part of the process involves feeding the lines L₁,L₂ of overlapping material sheets 71, 72 in the direction of the arrowA₃ through an apparatus 74 and folding it in half in the direction ofthe arrow B along a central fold line C_(L) into an assembled web. Theassembled web can then be wound into a roll in the same way as the rolldescribed in FIG. 4A or 4B above.

Alternatively, two lines of individual sheets arranged partiallyoverlapping in the longitudinal direction as shown in FIG. 2 can beused. The folding can then be carried out in the direction of the arrowB as shown in FIG. 7B or in the opposite direction said arrow.

FIG. 8A shows a plan view of a first part of a process for making a rollof material sheets according to a second example of the second preferredembodiment of the invention. As in the first example, individual sheets81, 82 of a respective first and second line L₁, L₂ are fed in thedirection of the arrow A and are arranged end-to-end, with the materialsheets 82 of the second line L₂ of sheets indexed to form an overlap of50% between subsequent sheets in the longitudinal direction. Thelongitudinal overlap has a length X₂ that in this example is 50% of thelongitudinal length X₁ of the material sheets. The transverse overlap Y₂in this example is 50% of the transverse width Y₁ of the materialsheets. The process involves feeding the lines L₁, L₂ of overlappingmaterial sheets 81, 82 in the direction of the arrow A through a firstapparatus 84 and folding it in the direction of the arrow B along afirst fold line F₁. The first fold line F₁ coincides with theoverlapping side edge 85 of the second line L2. During folding a firstouter, non-overlapping edge 86 of the lower, first line L₁ of materialsheets, which edge 86 is folded inwards over and fully covering thetransverse overlap Y₂.

As shown in FIG. 8B, the web comprising partially overlapping and foldedmaterial sheets 81, 82 shown in FIG. 8A are fed in the direction of thearrow A through a second apparatus 87 and folding the web in thedirection of the arrow C along a second fold line F₂. During folding asecond outer, non-overlapping edge 88 of the upper, second line L₂ ofmaterial sheets is folded inwards over and fully covering the overlapY₂. The assembled web can then be wound into a roll in the same way asthe roll described in FIG. 4A or 4B above.

Alternatively the assembled web is created by simultaneously folding theouter edge of the lower line of material sheets upwards and inwards, andthe outer edge of the upper line of material sheets downwards andinwards. Both folding arrangements create an assembled web comprisingconsecutive partially overlapping pairs of substantially V-shaped,opposed and interleaved material sheets.

The same effect, using partial overlap in the transverse direction maybe achieved at other degrees of overlap. For instance, with a transverseoverlap of ⅓ of the transverse width, the sheets on either side of theoverlap may be folded in half towards to create an assembled web.Alternatively, with a transverse overlap of ⅔ of the transverse width,the sheets on either side of the overlap may be folded along alongitudinal fold line located at approximately ⅓ of the width from theouter edges of the respective of the first and second line of sheets tocover a part of the overlap and create an assembled web. The examplesdescribed above for the second preferred embodiment may also apply toexamples using a variable overlap in the longitudinal direction.

In the above embodiments, individual sheets in the line or lines ofmaterial sheets cut from a continuous web are separated by a straight,transverse cut at right angles to the longitudinal axis of therespective line of material sheets. FIG. 9A shows an alternativeexample, where a transverse cut 90 has the shape of a sinusoidal curvewith an apex 91. The apex 91 forms a leading edge of each material sheet92 in a line L of sheets. The process involves feeding a web of discretematerial sheets 92, placed end-to-end in their longitudinal direction,through an apparatus 93 arranged for displacing the discrete materialsheets 92 so that an overlap 94 is created by adjacent material sheetsin their longitudinal direction. The direction of feed is indicated bythe arrow A. This is achieved by controlling the relative speed of afirst and a second conveyor 95, 96. The apparatus 93 for displacing thediscrete material sheets 92 is provided with a device (not shown) forcontrolling the vertical position of the leading edge of a materialsheet relative to the rear edge of a preceding sheet is provided at thelocation where the material sheets are passed from the first to thesecond conveyor. In the example shown, the length X₂ of the longitudinaloverlap 94 is ⅓ of the length X₁ of a material sheet 92.

As shown in FIG. 9B, the apex 91 of the sinusoidal curve in FIG. 9Acoincides with a fold line F and the sinusoidal curve is symmetricalabout a central axis coinciding with the said fold line F in the planeof the material sheets. The web of overlapping material sheets 92 is fedthrough a second apparatus 97 arranged to fold the sheets 92 along afold line F coinciding with the longitudinal centreline C_(L) of thematerial sheets 92, as shown in FIG. 9A. According to the example shownin FIG. 9B, the left hand side 98 of each material sheet is displacedupwards and folded over the right hand side 99 of the material sheet 92,as indicated by the arrow B, as seen in the direction of feed, asindicated by the arrow A, of the assembled web of material sheets 92.The overlapping and folded material sheets 92 can then be fed as acontinuous assembled web 100 between opposing rollers and/or conveyors(not shown) and is subsequently subjected to a winding operation.

In the above embodiment, the apex is described as forming a leadingedge. However, the apex can also form a trailing edge at the rearmostend of each material sheet in a line of sheets.

In addition to the overlap and folding described above, adjacentmaterial sheets can be interlinked by one or more alternativearrangements in order to achieve a desired friction between contactingsurfaces of said material sheets.

One alternative way of modifying the friction between overlappingsections of material sheet is the use of an embossing step performed onat least a portion of the overlap. According to one example theembossing is carried out by passing the assembled web of pre-cut andpartially overlapping material sheets through a nip between a pair ofcylindrical rolls. The rolls may be arranged to apply a desired amountof pressure onto at least a portion of the overlapping sections and/orto apply pressure over a predetermined surface area of each overlappingsection. Alternatively, a pair of rolls can apply continuous pressurealong the edges of the assembled web of sheets, allowing the said edgesto be provided with a decorative pattern that provides enhanced frictionin the region of each overlap. In the above examples, one or both rollsmay be patterned in order to emboss the compressed portions to apredetermined degree.

Embossing or compression of selected portions of adjacent materialsheets can be carried out after the overlapping procedure shown in FIG.2, or after the folding procedures shown in FIG. 3A, 3B or 5, prior tothe winding operation.

According to a further alternative way of modifying the friction, thematerial sheets can be interlinked by a friction enhancing coatingapplied onto at least a portion of the overlapping sections betweenadjacent sheets. A coating of this type is applied to at least a portionof one or both ends of each sheet in an assembled web of materialsheets, prior to the sheets being displaced into their overlappingpositions. The coating is applied by a single roller or a pair ofrollers, or by spraying. Coatings of this type will modify the surfacefriction of at least one of the surfaces in an overlapping section. Thecoating preferably creates a brittle or crystalline bonding betweencontacting surfaces, which bond will break as a preceding material sheetis withdrawn from the dispenser.

According to a similar alternative way of modifying the friction, thematerial sheets can be interlinked by an adhesive on at least a portionof the overlap between adjacent sheets. Suitable adhesives includeliquid, curable adhesives or hot-melt adhesives. Such adhesives areapplied in the same way as the coatings described above. As statedabove, the adhesive is applied prior to the sheets being displaced intotheir overlapping positions.

The invention is not limited to the above embodiments, but may be variedfreely within the scope of the appended claims.

1-22. (canceled)
 23. A roll of material sheets, which material sheetshave a longitudinal direction and a transverse direction, the rollcomprising discrete material sheets which partially overlap and arefolded at least once in the longitudinal direction, which longitudinaldirection corresponds to the winding direction of the roll, the materialsheets being interlinked in such a way that, when a first material sheetis extracted, a predetermined part of a subsequent material sheet is fedout, and the material sheets are provided with an interlinking frictionenhancing means placed in the overlap between adjacent material sheets.24. The roll according to claim 23, wherein the material sheets areinterlinked by an overlap of at least 25% of the length of an unfoldedmaterial sheet in its longitudinal direction.
 25. The roll according toclaim 24, wherein the material sheets are interlinked by an overlap ofup to 50% of the length of an unfolded material sheet in thelongitudinal direction.
 26. The roll according to claim 23, wherein thematerial sheets are interlinked by an embossing on at least a portion ofthe overlap.
 27. The roll according to claim 23, wherein the materialsheets are interlinked by a friction enhancing coating on at least aportion of the overlap between adjacent sheets.
 28. The roll accordingto claim 23, wherein the material sheets are interlinked by an adhesiveon at least a portion of the overlap between adjacent sheets.
 29. Theroll according to claim 23, wherein the degree of overlap varies fromthe center of the roll to the outer periphery of the roll.
 30. The rollaccording to claim 29, wherein the degree of overlap is at least 25% ofthe length of an unfolded material sheet in its longitudinal directionat the center of the roll and increases towards the outer periphery ofthe roll.
 31. The roll according to claim 30, wherein the degree ofoverlap is up to 50% of the length of an unfolded material sheet in thelongitudinal direction at the outer periphery of the roll.
 32. The rollaccording to claim 23, wherein the material sheets are folded twice inthe longitudinal direction, and the distance between the folds is atleast half the width of a sheet in the transverse direction.
 33. Theroll according to claim 23, wherein opposing end portions of each sheetare folded once in opposite directions along a transverse fold line andadjacent sheets are interlinked in such a way that each folded endportion encloses the adjacent folded end portion.
 34. The roll accordingto claim 23, wherein the partially overlapping material sheets comprisetwo parallel lines of individual material sheets placed on top of eachother.
 35. The roll according to claim 34, wherein each alternate sheetof overlapping material sheets is placed with its transverse rearportion arranged on top of a transverse front portion of a subsequentsheet.
 36. The roll according to claim 35, wherein the material sheetsare interlinked by a fixed or varying longitudinal overlap of at least25% and up to 50% of the length of an unfolded material sheet in itslongitudinal direction.
 37. The roll according to claim 36, wherein thematerial sheets are interlinked by a transverse overlap selected between30% and 100% of the transverse width of the material sheets.
 38. Theroll according to claim 23, wherein the material sheets are separated bya transverse cut having the shape of a curve having at least one apex,where the apex forms a leading or trailing edge of each material sheetin the line.
 39. The roll according to claim 38, wherein the apexcoincides with a fold line.
 40. The roll according to claim 39, whereinthe curve is symmetrical about an axis coinciding with the fold line inthe plane of the material sheet.
 41. The roll according to claim 23,wherein the roll is a center roll, whereby the material sheets areextracted from the center of the roll.
 42. The roll according to claim23, wherein the roll is a peripheral feed roll whereby the materialsheets are extracted from the periphery of the roll.
 43. The rollaccording to claim 23, wherein the material sheet is a tissue sheet, ora material sheet comprising a non-woven or equivalent wiping material.